Machine for grinding the edges of lenses



Mar. 2%), 11923.

E. W. CLARKE MACHINE FOR GRINDING THE EDGES OF LENSES 2- sheets-sheet l Filed Apr.

witmeoo E. w. CLARKE MACHINE FOR GRINDING THE EbGES OF LENSES Mar. 20 1923.

2 sheets-sheet Filed Apr.

Patented Mar. 26 1923.

EDWARD W. CLARKE, OF FREIDONIA, NEW YORK.

MACHINE FOR GRINDING THE EDGES F LENSES.

Application filed April 7,

To all whom it may concern Be it known that I, EDWARD W. CLARKE, a citizen of the United States, residing at Fredonia, in the county of Chautauqua and State of New York, have invented certain new and useful Improvements in Machines for Grinding the Edges of Lenses; and I. do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in lens edge grinders of the type employed in shaping the lenses of eyeglasses. The prinlo cipal machines of this character now in use,

are provided with a tilting carriage provided with means for holding the lenses to be ground and for rotating the lenses against a grinding wheel. Experience has shown however that the bearings which pivotally support the carriage, become so worn in little time, as to make it practically impossible to obtain, an accurately ground edge on the lenses. One of the foremost as objects of my invention is to provide an improved arrangement of supporting bearings for the carriage, so as to effectively overcome the objection mentioned.

The machines of the present day type so usually employ a coiled spring and adjusting means therefor acting on the carriage to hold the work against the grinding wheel with any desired degree of pressure. This necessitates however that the carriage be provided with a handle for tilting it forwardly from the grinding wheel when inserting or removing lenses, and it is either necessary to hold said carriage in its foremost position by hand, or to provide some catch mechanism for obtaining this result. A further aim of my invention however is to employ a shiftable weight active either to hold the work against the grinding wheel with various degrees of pressure, or to tilt the carriage forwardly and thus move the Work out of contact with the grinding wheel. A still further object is to provide novel means for holding the lenses while they are being ground and for quickly releasing them when the grinding operation is completed.

A still further object is to provide a grinding wheel having separate surfaces for grinding straight and bevelled edges on the lenses, said wheel being shiftable axially to brin any desired surface into play.

W ith the foregoing in view, the invention 1921. Serial No. 459,290.

resides in the novel construction and association of parts hereinafter described and claimed, the descriptive matter being supplemented by the accompanying drawings.

Figure 1 is a front elevation partly in section, showing a lens edge grinder constructed in accordance with my invention.

Figure 2 is a side elevation showing the adjustable weight in position for holding the work against the grinding wheel.

Figure 3 is a duplicate of Fig. 2 with the exception that it illustrates the manner in which the weight may be adjusted to tilt the carriage away from the grinding wheel.

Figure 4c is a perspective view of the adj ustable weight and its carrying arm.

Figure 5 is a top plan view showing the machine set for grinding a straight edge on the lens.

Figure 6 is a view similar to Fig. 5 but illustrating the method of grinding a bevelled edge.

In the drawings above briefly described, the numeral 1 designates a base from which a pair of end bearings 2 and a plurality of spaced intermediate bearings 3 rise, said bearings being in horizontal alinement and rotatably supporting a horizontal shaft 4. This shaft pivotally supports the work carriage 6, which carriage is provided at its lower edge with a horizontally elongated bearing 7 whose lower side is provided with notches 8 receiving the intermediate bearings 8, while the end bearings 2 are located. at the ends of said bearing 7. The upper side of the bearing 7 is provided with notches 9 and 10 located near its ends and by reference to Fig. 1, it will be seen that the shaft t extends across these notches as well as across the notches 8, said shaft being provided with pinions 11 and 12 located respectively in the notches 9 and 10. The pinion 11 is of the spur type while pinion 12 is preferably of spiral form to mesh with a worm 13 on an operating shaft 1 this shaft being rotatably mounted in a suitable bearing 15 on the base 1 and being provided at its front end with a hand wheel 14 whereby it may be rotated at will.

Above the bearing 7, the carriage 6 is provided with two end bearings 16 and two spaced intermediate bearings 17 which are spaced also from said bearings 16. A. hori- Zontal shaft 18 is rotatably supported in two of the bearings 16 and 17 and is provided with a spur gear 19 meshing with the pinion 11, the inner end of said shaft being able'in a socket 26 in one of the bearings 17 and is forced outwardly by a coiled spring 27 located in-said socket. Head is carried by a shaft 28 rotatably and slidably mounted inthe right-hand l'aearings 16 and 17 and between these bearings, 'a spiral gear 29 is keyed onthe shaft 28 for mesh with the pinion 12, the keying arrangement however being such as to'permit the shaft 28 to slide through the hub of thegear. This sliding is 'effected in one direction by the spring 27 and in the other direction by a hand operated nut 30 which is threaded on the other end of the shaft 28 and is adapted for contact with the adjacent bearing 16 when turned in a direction'to move the shaft 28 outwardly and thereby withdraw the head 25 from contact with the lens.

Fortilting the carriage 6 either toward or from the grinding wheel 31 with which the machine is equipped, provide a shiftable weight 32, said weightibeing here shown mounted on an arm 33 which is provided with portions extending oppositely from the vertical plane in which the pivotal axis 4 of the carriage is located. By shifting the weight to one side of this plane (see Fig. 2) the carriage is tilted toward the wheel 31 and by properly adjusting said weight, it will be seen that the work may be held against the grinding wheel with any desired amount of pressure. By shifting the weight 32 to the other end of the arm 33 however (see Fig. 3), the carriage 6' is tilted forwardly and held in this position while either removing the work from the machine or inserting such work. This is greatly advantageous over the usual coiled springs which are used for tilting the carriage in a manner to hold the work against the grinding wheel. These springs are of course adjustable to obtain various pressures, but they do not act in any manner to tilt the carriage to an inactive position and to hold it in such a position.

VV'ith the same machine, it is highly desirable to be able to grind eitherstraight or bevelled edges on lenses. To permit the use of my machine for these purposes, I provide the edgeof the grinding wheel 31 with bevelled corners 34 and make provision for shifting the wheel axially so as to produce either straight edge grinding or bevelled edge grinding as seen in Figs. 5 and 6. In the present showing, the shaft 35 of the wheel 31 is both rotatable and slidable in suitable bearings 36 so that it may be axially shifted to adjust thewheel as'required, and

' I have shown said shaft provided with circumferential grooves 37 for co-action with a suitable latch 38', whereby the shaft and wheel may be held in any position at which they may be set. T

By providing the several improved features herein shown and described, a machine is provided which is much more durable, less expensive, and more efficient and durable than the machines now in common use, particular attention being directed to the novel bearing arrangement for supporting the carriage 6to the shiftable weight 32 for tilting the carriage, and to the axially shiftable features of improvement.

Since excellent results may be obtained from the general construction and association of parts shown, this arrangement may be employed if desired, but it is to be understood that the present disclosure is for illustrative purposes only and that within the scope of the invention as claimed, the improvements may be embodied in numerous forms other than those shown.

I claim:

1. In a lens edge grinder, a base, a cargrinding wheel 31. these being the principalriage above said base having a horizontally elongated bearing provided in its upper side with a pair of notches located near its ends,

the lower side of said bearing having a plurality of additional notchesbetween said of notches, a pair of'bearings carried rig-- idly by, the upper side of said elongated bearing between said first named notches, end bearings carried rigidly by the upper side of said horizontally elongated hearing at the outer sides of said first named notches said pair of bearings and said end bearings being in axial alinement with each other, a pair of lens-holding and rotating shafts each of'which is mounted in one of Said pair of bearings and one of said end bearings, gears in said first named notches mounted on said first named shaft, and other gears on said pair of shafts between said end bearings and said pair of bearings, said other gears meshing with said first named gears.

2. A carriage for lens edge grinders com prising a horizontally elongated bearing provided in 'its'upper'side with a pair of said bearing having a shaft-receiving bore above the bottoms of said first named notches and below the tops of said additional notches, a pair of bearings carried rigidly by the upper side of said horizontally elongated bearing between said first named notches, and end bearings carried rigidly by said upper side of the horizontallv elongated hearing at the outer sides of said first named notches, said pair of bearings and end bearings being in axial alinement with each other and being adapted to support lensholding and rotating shafts, the spaces between said pair of bearings and said end bearings as well as said first named notches being adapted to receive gearing for driving the lens holding shafts from the first mentioned shaft.

3. The combination with a pivoted work carriage of a lens edge grinder; of an arm secured to said carriage and having portions extending in opposite directions beyond its pivotal axis, and a weight on said arm movable onto one of said portions to tilt the carriage from the grinding wheel and movable on the other portion to tilt said carriage toward the grinding wheel.

a. In a lens holder for edge grinding machines, a relatively stationary but rotatably mounted head, a second head movable toward and away from said relatively stationary head and co-operable therewith for holding a lens, a pair of spaced bearings alined with said movable head, one of said bearings having a socket receiving said movable head, a spring in said socket for projecting said movable head toward said relatively stationary head, a shaft rotatable and slidable in said bearings and carrying said movable head, a nut threaded on the other end of said shaft for sliding the same to retract the movable head, from the relatively stationary head, and a driving Wheel between said bearings through which said shaft passes slidably.

5. A lens edge grinder comprising lens holding and rotating means, a grinding wheel having different surfaces for grinding plain and bevelled edges, a shaft on which said wheel is mounted fixedly, said shaft being mounted for longitudinal shifting to set said wheel to bring the desired grinding surface into play, and a latch stationary with respect to said shaft, the latter having circumferential grooves each in a plane at truly right angles to the shaft axis to receive said latch and to hold the shaft and wheel in any desired position.

1111 testimony whereof I have hereunto set my hand,

EDl/VARD W. CLARKE. 

